He has gone from being a chiselled hunk with rock hard abs to cutting a rather frumpy, sad figure - just what HAS happened to Rob Kardashian?

It can't be easy being a member of one of the most beautiful families in the world - but Rob Kardashian seems to have let his sister's get the better of him.

From his sad dash out of Paris just hours before sister Kim Kardashian's wedding to Kanye West to his Twitter meltdowns, the sock designer has cut a bizarre figure in the last 12 months - and we don't mean his weight gain.

(Photo: WENN)

(Photo: WENN)

Downcast Rob dramatically pulled a no-show just hours before his sister Kim's wedding. It is thought the 27-year-old ditched the ceremony in Florence because he felt too self-conscious about his size to appear in photographs.

A source said how Rob's last minute departure caused rows among the Kardashian family and he was seen booking his flight back to LA in tears.

Celebrity trainer Gunnar Peterson told TMZ he had received a text message from the Rob when he returned from Italy. He said Rob is determined to "hit the ground running" with a new fitness regime and wants to work out every day until he feels slim again.

Rob's problems are thought to have begun just after his bitter break-up with UK chart topper Rita Ora.

(Photo: WENN)

(Photo: WENN)

She cheated on me with nearly 20 dudes while we were together... But I mean 20?!!!!' he tweeted in December 2012. "How can a woman who is so busy trying to start her own career have time to be with so many dudes while in a relationship?!, he tweeted.

For good measure, he added: "I am actually disgusted."

Rita then added she never actually thought the pair were in a relationship. Ouch.

Earlier this year, tormented Rob tweeted more than a few bizarre messages, including: "So i found out i was trending for being fat… thank you all it really made my day. And to the blogs saying i went to fat camp or rehab LOL then why am i still fat u fools?? y'all must have run out of real news."

With rumours Kris Jenner wants to stage an intervention, we just hope Rob gets better soon. And he stops dwelling on his weight.